ALB and periodontitis: Human paraffin-embedded gingival tissues were collected from patients with Pg-colonized periodontitis. Deparaffinization of 5 m sections was performed by several xylene, ethanol, and water washes. Endogenous peroxidase activity was inhibited by the addition of hydrogen peroxide in methanol, followed by blocking of nonspecific antibody binding with 1% bovine serum albumin and 1% normal goat serum in PBS.